Looks like a flavor of MP4 (MPEG-4 Part 14) container, with H.264/AVC video.
Have you tried
Avisynth with the
FFMS2 source filter? If that works, you can use pretty much
any x264 or x265 GUI that you like (they all support Avisynth input).
Otherwise, you can try with
FFmpeg directly - with your preferred FFmpeg GUI, if you don't like the command-line.